1. Field of the Invention
The present invention relates to an angle indicator. Particularly, the present invention is directed to an angle indicator for indicating an angle of a structure with respect to the horizontal plane.
2. Description of Related Art
A variety of devices are known in the art for measuring the angle of a structure with respect to a reference point or location, such as another structure. Of such devices, certain devices are directed to measuring the elevation of the head of a hospital patient bed.
Accurate measurement of the elevation of the head of a patient bed can be vital to decrease rates of aspiration pneumonia in patients. In 1992, Torres et al. showed that placing a patient in a semirecumbent position (i.e., at a 45-degree angle) decreases aspiration of gastric contents to the airways in intubated and mechanically ventilated patients (“Pulmonary aspiration of gastric contents in patients receiving mechanical ventilation: the effect of body position,” Ann. Intern. Med. 116(7):540-3 (1992)). In 1993, Kollef showed that supine head positioning during the first 24 hours of mechanical ventilation was independently associated with mortality (“Ventilator-associated pneumonia. A multivariate analysis,” JAMA, 270: 1965-1970 (1993)). Later, Fermandez-Crehuet et al. showed that the main risk factors for developing nosocomial infections among intubated patients were intrinsic (“Nosocomial infection in an intensive-care unit: identification of risk factors,” Infect. Control Hosp. Epidemiol. 18(12):825-30 (1997)). Significant extrinsic risk factors identified included maintaining the head of the patient's bed in a horizontal position, particularly less than thirty degrees with respect to the horizontal. In fact, this variable presented the highest increase of the infection hazard ratio.
In 1997, the Centers for Disease Control and Prevention issued Guidelines for Preventing Heath-Care-Associated Pneumonia that recommended that patients receiving mechanical ventilation have the head of the bed elevated 30-45 degrees above the horizontal to prevent nosocomial pneumonia.
Thus, a compelling need has been recognized to elevate the head of a patient's bed in order to preserve the health of patients. In fact, the Institute for Healthcare Improvement (IHI) has instituted a “100,000 lives” campaign to prevent avoidable hospital deaths. One of the six areas they identified were deaths due to Ventilator-Associated Pneumonia (VAP) with the objective of preventing 100,000 deaths between January, 2005 and January, 2006 by educating hospital staff regarding the importance of maintaining adequate head of bed elevation and improving rates of adequate head-of-bed elevation. According to the IHI, VAP is the leading cause of death among hospital-acquired infections, wherein hospital mortality of ventilated patients who develop VAP is 46%, compared to 32% for ventilated patients who do not develop VAP. The IHI estimates that VAP adds an estimated cost of $40,000 to a typical hospital admission.
A number of devices have been proposed to maintain adequate head of bed elevation. A first example includes a track underneath the bed running the length of the bed. Angles from ten to sixty degrees above the horizontal in five-degree increments are indicated. A bar extends from the head of the bed to the track. As the head of the bed is elevated, the bar moves along the track and the elevation of the head can be determined by reading the angle indicated along this bar.
However, there are significant drawbacks relating to this device. First, the health care provider (e.g., nurse, physician, etc) must bend down and look under the bed to read the angle. Second, hospital beds are sometimes placed on a tilt in the Trendelenberg position. Since the bed angle only measures the elevation of the head relative to the bed, when the entire bed is not level, the bed angle indicator does not work. Practically, since beds are often in the Trendelenberg position, nurses don't bother to look at the angle indicators since they don't accurately reflect the head-of-bed elevation. Finally, this device indicates angles from ten to sixty degrees. This only serves to confuse and distract nurses who are already having to deal with a barrage of information. There is no need to know if a bed is elevated at a ten or fifteen degree angle. Because there is so much information given (i.e., in 5-degree increments), all the numbers are difficult to read and adequacy of elevation (i.e., at least 30 degrees) cannot be easily displayed. Due to the foregoing reasons, there is lack of compliance in maintaining hospital beds at an appropriate angle.
Another device used to detect bed elevation includes a small ball that runs inside a covered groove on the arm of a bed. Angles are indicated along the curve. While this device has the advantage of working even when the bed is in Trendelenberg position, it is still very difficult to read and does not clearly indicate when the head of the bed is adequately elevated. Specifically, this device relies on the user to come very close to read the angle of elevation and then determine whether that is adequate.
Such conventional methods and systems generally have been considered unsatisfactory for their intended purpose. Despite the availability of these systems, their difficulty to use has resulted in very low levels of compliance by healthcare facilities in maintaining proper angles of inclination of patients.
Thus, although potential solutions to the problem of maintaining adequate head of bed elevation have been developed, such as discussed above, there still remains a continued need in the art for a method and device of maintaining adequate head of bed elevation that is both accurate and simple. There also remains a need in the art for a bed angle indicator that is inexpensive and easy to make. Moreover, there is a long felt need for a bed angle indicator that is easy to use to raise levels of compliance by healthcare staff. The present invention provides a solution for these problems.